What it is and what it does
The Siemens 3RT1023-1AP60 is a SIRIUS S0 power contactor designed for switching motor loads in control panels. It's rated for 4 kW at 400 V AC-3 duty, 4.5 kW at 500 V, and 5.5 kW at 690 V, so it handles three-phase motors up to those power levels. The AC-2 rating at 400 V is also 4 kW, covering slip-ring motor applications. AC-4 rated current is 8.5 A at 400 V for reversing or inching duty. It mounts on a 35 mm DIN rail per EN 50022, either snapped on or screwed. The 45 mm width fits standard panel layouts. Screw-type terminals on the main circuit accept 2x (0.5...1.5 mm²), 2x (0.75...2.5 mm²), and up to 2x 4 mm² solid, or 2x (1...2.5 mm²), 2x (2.5...6 mm²), and max 2x 10 mm² stranded. AWG equivalents are 2x (16...12), 2x (14...10), and 1x 8.
Where it fits in the panel
Size S0 means it's a compact contactor for small to medium motor loads. It can be mounted side-by-side without derating, and the IP20 front protection keeps fingers out during panel access. The terminal area is IP00, so live parts are exposed when wiring — standard for panel-mounted contactors. Ambient range is -25 to +60 °C during operation, with pollution degree 3 (industrial environment). Mechanical life is 10 million operations typical. For short-circuit protection, type 2 coordination requires a 25 A gL/gG fuse; type 1 coordination allows a 63 A gL/gG fuse. The auxiliary contacts (built-in or add-on) are rated for 10 A at 24 V AC, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V — enough for PLC inputs or relay coils.
Sourcing decision
If you're filling a BOM line or replacing a failed unit, this part is a direct fit for any panel designed around a SIRIUS S0 contactor. The 45 mm width and screw terminals match the standard footprint. Quoted to order against an RFQ.